People conduct billions of searches for documents worldwide every day. This searching involves searching for information in documents, i.e. using the index relation {keywords}→Indexr→{Documents}. This information retrieval is conducted by search engines such as Google.
People also search continuously for their kids, purse, credit cards, keys, lipstick, passport, seniors, car or any conceivable person or object in the spatial domain. It is known in the prior art that cargo is tracked e.g. by supplying GPS chips on cargo boxes. It is also known in the prior art that RFID tags can be used to track kids, where an RFID reader is in a mobile phone. This system is described in US2011/0227726 A1, which is cited here as reference.
It is also known in the prior art that RFID tags can be used to deliver information via WLAN connections. EP1908250B1 provides a mobile phone with RFID reader and WLAN transmitter integrated on a SIM card. It is used e.g. to realise a museum guide to provide info about exhibited objects via WLAN. This document is cited here as reference.
RFID's can be attached conveniently to articles, e.g. US2010/0090011 describes an RFID tag that has an adhesive on a first surface for attaching to an article. This document is cited here as reference.
It should also be noted that in the prior art sonar systems have been used to locate fish, and radar has been used to locate for example airplanes.
Also, when the inventor loses his mobile phone, he usually finds it by using another mobile phone to call it in accordance with the prior art.
Despite all these technologies, the average person spends a lot of his time every day to keep track of his belongings. Quite clearly, the prior art has substantial shortcomings. The prior art is not suited to managing the whole fleet of essential items that a person owns dynamically in changing practical life situations.